Sculpt

You can add a sculpt layer to modify the shape of the mesh at a given frame or remove artifacts. If you sculpt a shape and want to keep it “parented” to the mesh enable tangent space.

For example if you have a character turning his head and you want to make his nose bigger you should enable tangent space, if not the new nose will twist as the character turns his head.

Tangent space tends to be sensitive if you sculpt on top of an area that is deforming or stretching too much, as the space is created on the fly for each vertex, in order to fix any bad deformation or noise in this area just paint a mask around it and add some iterations, like 5 to 10 iterations.